JPH10260605A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of attaining stable coating with a proper and specified amount of a releasing agent over a long period. SOLUTION: A press-contact roller 5b coming into press-contact with a cleaning web 5a is provided between the feeding and winding sides of the cleaning web 5a. The cleaning web 5a on the feeding side is dipped in the releasing agent 8 of an oil pan 7 and a pair of pinch rollers 9 for regulating the impregnate degree of the releasing agent 8 in the cleaning web 5a is provided above the releasing agent 8. Thus, the cleaning web 5a can function as a cleaning member and a releasing agent coating member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic or electrostatic recording type image forming apparatus such as a printer or a copying machine, and has a fixing device.

[0002]

2. Description of the Related Art A fixing device of a copying machine will be described below as an example of an image forming apparatus.

A fixing device of a medium / high-speed copying machine and a color copying machine of a black-and-white copying machine often has a cleaning means and a release agent applying means.

FIG. 8 shows an example of a conventional fixing device of a monochrome copying machine. The recording medium 1 to which the unfixed toner image has been transferred in the transfer unit (not shown) is conveyed in the direction A, and the fixing roller 2
And a nip formed by the pressure roller 3. The fixing roller 2 is heated by a heater 4. Pressure roller 3
Is pressed against the fixing roller 2 at a predetermined pressure, and the rollers 2 and 3 rotate in directions B1 and B2, respectively. The recording medium 1 that has reached the nip between the rollers 2 and 3 has an unfixed toner image fixed by the heat and pressure, and is discharged in the direction A.

[0005] The fixing roller 2 is cleaned by a cleaning device 5 to remove a small amount of toner and paper dust adhered thereto. The cleaning device 5 includes a cleaning web 5a, a pressing roller 5
b, a winding mechanism (not shown), etc., wherein the cleaning web 5a is a band-shaped nonwoven fabric, and the pressing roller 5b is a heat-resistant sponge roller.

The cleaning web 5a is wound in the direction C by a predetermined amount each time the recording medium 1 passes one nip portion between the fixing roller 2 and the pressure roller 3, and is replaced with a new one when the winding is completed. The cleaning web 5 is impregnated with silicone oil as a release agent in advance, and the oil is applied to the fixing roller 2. Thus, the cleaning device 5 serves both as a cleaning unit and a coating unit.

Next, an example of a conventional fixing device of a color copying machine is shown in FIG. Parts having the same functions as the above-described parts shown in FIG. 8 are denoted by the same reference numerals, and description thereof is omitted.

In many fixing apparatuses of a color copying machine, a release agent applying device 6 is provided independently. Coating device 6
Consists of an application roller 6a, pumping rollers 6b and 6c, and a regulating blade 6d, and is rotated in the direction D by a driving source (not shown). Silicon oil 8 as a release agent held in an oil pan 7 is pumped up to the application roller 6a by pumping rollers 6b and 6c, and the silicon oil 8 is regulated to a desired amount by a regulating blade 6d and then applied to the surface of the fixing roller 2. I do.

Although the above-described cleaning device 5 is also provided, the cleaning web 5a is not impregnated with the silicone oil 8, and in this case, does not have a role of a mold release agent applying means.

When the above-described coating means is used, the amount of silicone oil applied to the recording medium is about 0.5 to 1 mg per A41 sheet in the case of a black-and-white copying machine, and 20 to 20 mg per A41 sheet in the case of a color copying machine. Generally, it is about 40 mg.

[0011]

However, the above conventional example has the following problems. In a recent fixing device of a color copying machine, the required amount of a release agent is smaller than before.

As in a black and white machine, the cleaning web 5a
It is too small to impregnate and apply, however, it is difficult to reduce it to some extent by the conventional method. For example, using the coating apparatus of the color copying machine shown in the conventional example, when trying to achieve a release agent application amount of about 10 mg per A4,
The regulation cannot be performed unless the regulating blade 6d is pressed against the application roller 6a at a considerably high pressure. However, when the pressure is set to a high pressure, the edge of the regulating blade 6d is worn, and the regulating force is quickly reduced, such as looseness.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus provided with a fixing device capable of applying an appropriate amount and a constant amount of a release agent to a recording medium stably over a long period of time.

[0014]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides:
A fixing device having at least one or more fixing rollers for fixing a recording material to a recording medium, a heating unit for heating the fixing roller, a cleaning unit for cleaning the surface of the fixing roller, and an application unit for applying a release agent. In the image forming apparatus including the device, a single dual-purpose member that also functions as the cleaning unit and the coating unit, a unit that supplies a release agent to the dual-purpose member, and the dual-purpose member contacts the fixing roller. An image forming apparatus comprising: a regulating unit which is located between the part and the releasing agent supply unit and regulates an amount of the releasing agent contained in the dual-purpose member.

It is preferable that the dual-purpose member is a belt-shaped cleaning web. It is preferable that the cleaning is performed on the front surface of the cleaning web and the release agent is applied on the rear surface.

According to a preferred embodiment of the present invention, the cleaning web moves from the unwinding side to the winding side by a predetermined amount each time the recording medium passes through the fixing roller.
According to another aspect, it is preferable that the cleaning web is formed in an endless shape.

It is preferable that the regulating means has a pair of pinch rollers. According to another preferred aspect, the regulating means has a regulating blade and a backup member. According to still another preferred aspect, the regulating means has a plurality of deflection members forming a bent path.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to the present invention will be described in more detail with reference to the drawings. In the embodiment described below, the present invention is described as being embodied in, for example, an electrophotographic image forming apparatus as shown in FIG. 7, but the present invention is not limited to this.

In FIG. 7, in the electrophotographic image forming apparatus, a photosensitive drum 31 as an image carrier is rotatably provided, and the photosensitive drum 31 is uniformly charged by a primary charger 32. An information signal is exposed by such a light emitting element 33 to form an electrostatic latent image, and is visualized by a developing device 34. Next, the visible image is transferred to the recording medium 1 such as transfer paper by a transfer charger 35, and a recording agent as a developer is fixed by a fixing device 40 to obtain a permanent image. The transfer residual toner on the photosensitive drum 31 is removed by the cleaning device 36.

Embodiment 1 Embodiment 1 of a fixing device according to the present invention will be described below with reference to FIG. The same reference numerals are given to the same functional parts as in the conventional example, and the description is omitted.

The cleaning device 5 of the fixing device 40 according to the present embodiment includes an unwinding shaft 12a that unwinds the cleaning web 5a immersed in the release agent 8 held in the oil pan 7,
Between the winding shaft 12b for winding the cleaning web 5a and the winding web 12b,
1 includes a pair of pinch rollers 9 for regulating the amount of a release agent such as silicone oil impregnated in a, a guide roller 10, and a pressure contact roller 2 pressed against the fixing roller 2.

In the above-mentioned cleaning device 5, the cleaning web 5a is wound on the winding shaft 12a every time the recording medium 1 passes one nip portion between the fixing roller 2 and the pressure roller 3.
Is wound in the C1 direction by a predetermined amount. The cleaning web 5a wound on the unwinding shaft 12b is immersed in the release agent 8 held by the oil pan 7, and the release agent 8 naturally impregnates. Further, the cleaning web 5a is connected to the unwinding shaft 12
When being unwound in the C2 direction from a, the excess release agent 8 on the surface of the cleaning web 5a is squeezed down by a pair of pinch rollers 9 as a means for regulating the amount of oil.
Since the release agent is regulated in an area where the cleaning web 5a is sent upward, an excess of the release agent 8 is collected in the oil pan 7 below.

It is desirable to wind up the cleaning web 5a by a fixed amount for each recording medium using a stepping motor or the like.

According to the present embodiment, it is possible to increase the amount of application compared to the method of applying a release agent previously impregnated on the cleaning web 5a of FIG. 8 shown in the conventional example. However, the amount of coating can be reduced as compared with the method having an independent coating device shown in FIG.

Further, since the cleaning web 5a in this embodiment has no element that changes with time, such as abrasion or settling of the regulating blade shown in FIG. 9, it is possible to always maintain a constant coating amount. It is.

Further, since the apparatus itself can be simplified, the cost can be greatly reduced as compared with, for example, the fixing apparatus of the conventional color copying machine shown in FIG.

Further, the cleaning device of the present embodiment can change the amount of application to the recording medium 1 to some extent by changing the amount of winding of the cleaning web 5a. In other words, by increasing the winding amount per sheet, the unused portion of the cleaning web is more in contact with the fixing roller, so that the application amount of the release agent can be increased.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. The same functional portions as those in the conventional example and the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In this embodiment, cleaning and coating are performed using the front and back surfaces of the cleaning web 5a.

In this embodiment, in addition to the pressure roller 15, a second pressure roller 16 is pressed against the fixing roller 2, and between the first pressure roller 15 and the second pressure roller 16, two rollers are provided. Guide rollers 21 and 22 are disposed.

As in the first embodiment, the unwinding side of the cleaning web 5a is immersed in the release agent 8 held by the oil pan 7. The cleaning web 5a is a recording medium 1
Is wound in the C2 direction by a predetermined amount each time one sheet passes through the nip portion between the fixing roller 2 and the pressure roller 3. that time,
Since it passes through the pair of pinch rollers 9, the excess of the release agent 8 is squeezed.

Cleaning web 5a containing release agent 8
First reaches the contact portion between the first pressing roller 15 and the fixing roller 2. At this time, the X surface of the cleaning web 5a comes into contact with the fixing roller 2, and a predetermined release agent is applied to the fixing roller 2.

Further, when the recording medium 1 passes through the contact portion between the fixing roller 2 and the pressure roller 3 and the cleaning web 5a is wound up by a predetermined amount each time in the C2 direction, the second pressure contact roller 16 and a contact portion of the fixing roller 2. At this time, the Y surface of the cleaning web 5 a corresponding to the back surface of the X surface contacts the fixing roller 2. Since the cleaning web 5a is already in contact with the fixing roller 2 once,
Here, the release agent is hardly impregnated. However, since the Y surface is the back surface of the X surface contacted by the pressing roller 15, sufficient cleaning ability can be exhibited without contamination.

According to the present embodiment, although the configuration is slightly more complicated than that of the first embodiment, one cleaning member 5 is provided.
a, it is possible to divide the application section and the cleaning section, and by using the front and back surfaces, the dirt attached to the cleaning web does not adversely affect the application of the release agent. The ability of each of cleaning and application can be sufficiently exhibited.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG. The same reference numerals are given to the same functional parts as the conventional example and the first and second embodiments,
Description is omitted.

This embodiment is an example in which the cleaning web 5a is formed in an endless belt shape. The cleaning web 5a is wound around the pressing and driving roller 17 and the oil pan side roller 18, and the oil pan side roller 18
Is immersed in a release agent 8 held by an oil pan 7.
A pinch roller pair 9 is disposed between the two rollers 17 and 18 on the side of the fixing roller 2.

The pressing and driving roller 17 rotates by a predetermined angle each time one recording medium 1 passes, whereby the cleaning web 5a also moves. At this time, the excess oil is squeezed out by the pinch roller pair 9.

In this embodiment, the recording medium 1 is
This is suitable for a model where the amount of toner and paper powder adhered to the surface is not so large and the cleaning is not emphasized.

In this embodiment, the apparatus is greatly simplified.
Costs can also be very low.

Although the first to third embodiments have been described above, a part of the cleaning web 5a is not directly immersed in the release agent 8 as in these examples, but is separately separated on the surface of the cleaning web 5a. A configuration having a means for supplying the mold agent 8 does not contradict the gist of the present invention.

The cleaning web 5a is not necessarily a nonwoven fabric member as in the above embodiment, but may be any member having the ability to hold a release agent on itself such as a porous sheet member. The type and material are not limited.

Further, the pinch roller pair 9 is used as an example as a regulating means for squeezing excess oil from the cleaning web 5a, but the present invention is not limited to this means.

Next, some examples of the regulating means are shown in FIGS. FIG. 4 shows an example in which a pair of pinch rollers 9a and 9b are used as the release agent regulating means. The rollers 9a and 9b are pressed against each other by a spring 21. As for the material, one roller 9a is made of metal and the other roller 9b is made of rubber. In this case, it is desirable that both rollers 9a and 9b have a certain nip width.

FIG. 5 shows a means for regulating the oil amount by the backup member 22 and the regulating blade 23. The regulating blade 23 may be a rubber blade or a plastic blade, and the contact pressure may be adjusted by, for example, the spring 21 so as to have a desired regulating amount.

FIG. 6 shows a means for squeezing the cleaning web 5a to squeeze and remove excess oil. A bent path is formed by the deflecting members 24 and 25, and oil is dropped in the process.

[0045]

As is apparent from the above description, according to the present invention, a single dual-purpose member which also functions as a cleaning unit and a coating unit, a unit for supplying a release agent to the dual-purpose member, By having a regulating member that regulates the amount of the release agent contained in the dual-purpose member in a portion where the dual-purpose member is in contact with the fixing roller and the release agent supply unit, An appropriate amount and a fixed amount of the release agent can be stably applied over a long period of time. Therefore, a good image can be obtained over a long period of time. Also, the device is simplified,
Equipment costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a fixing device according to a first exemplary embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating a fixing device according to a second exemplary embodiment.

FIG. 3 is a configuration diagram illustrating a fixing device according to a third embodiment.

FIG. 4 is an explanatory view showing another example of the release agent regulating means.

FIG. 5 is an explanatory view showing still another example of the release agent regulating means.

FIG. 6 is an explanatory view showing still another example of the release agent regulating means.

FIG. 7 is a schematic configuration diagram illustrating an electrophotographic image forming apparatus in which the present invention is embodied.

FIG. 8 is a configuration diagram illustrating an example of a conventional fixing device.

FIG. 9 is a configuration diagram illustrating another example of a conventional fixing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording medium 2 Fixing roller 3 Pressure roller 4 Heating member 5 Cleaning device 5a Cleaning web (combined member) 5b Pressure contact roller 7 Oil pan 8 Silicon oil (release agent) 9 Pinch roller pair (release agent regulating means)

Claims (8)

[Claims] At least one or more fixing rollers for fixing a recording agent onto a recording medium, heating means for heating the fixing roller, cleaning means for cleaning the surface of the fixing roller, and release from the fixing roller An image forming apparatus including a fixing device having an application unit for applying an agent, a single dual-purpose member serving also as the cleaning unit and the application unit, and a unit for supplying a release agent to the dual-purpose member; An image forming apparatus, comprising: a regulating unit that regulates an amount of the release agent contained in the dual-purpose member, which is located at a position where the dual-purpose member comes into contact with the fixing roller and between the release agent supply unit. apparatus. 2. The image forming apparatus according to claim 1, wherein said dual-purpose member is a belt-shaped cleaning web. 3. The image forming apparatus according to claim 2, wherein the cleaning is performed on a front surface of the cleaning web, and a release agent is applied on a rear surface of the cleaning web. 4. The image forming apparatus according to claim 2, wherein the cleaning web moves from the unwinding side to the winding side by a predetermined amount each time the recording medium passes through the fixing roller. 5. An image forming apparatus according to claim 2, wherein said cleaning web is formed in an endless shape. 6. An image forming apparatus according to claim 1, wherein said regulating means has a pinch roller pair. 7. An image forming apparatus according to claim 1, wherein said regulating means has a regulating blade and a backup member. 8. An image forming apparatus according to claim 1, wherein said regulating means has a plurality of deflecting members forming a curved path.